Rolling with and without Slipping, during Epicycloids Generation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.880.63 ◽

2018 ◽

Vol 880 ◽

pp. 63-68

Author(s):

Iulian Popescu ◽

Ludmila Sass ◽

Alina Elena Romanescu

Keyword(s):

Planetary Gear ◽

Lubricant Layer ◽

Smooth Surfaces ◽

Original Idea ◽

Starting Point ◽

Rolling Without Slipping ◽

Significant Class

The starting point consists in the modality to generate epicycloids when two external circles are considered. The mobile circle is rolling on the fix circle without slipping, such as two arcs belonging to these circles are equal. The specialty literature presents an example with a simple planetary gear in which the “satellite porting” arm provides the rolling of the mobile circle on the fix circle. Our original idea, not approached in the specialty literature, considers the rolling with slipping of the mobile circle on the fix circle. Instead of the gears providing the rolling without slipping, two wheels with smooth surfaces are used now. The case when the two involved arc are no longer equal is analysed. Between them appear either frictions generating braking or “skating like” rolling when the lubricant layer is too thick. An analysis of the theoretical case when the slipping has a sense opposite to that of a normal rolling is also performer. A significant class of curves was obtained. Some are even epicycloids obtained with slipping, with other parameters.

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Rolling with and without Slipping during Orthocycloids Generation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.880.69 ◽

2018 ◽

Vol 880 ◽

pp. 69-74

Author(s):

Iulian Popescu ◽

Alina Elena Romanescu ◽

Ludmila Sass

Keyword(s):

Plane Curve ◽

Lubricant Layer ◽

Classical Form ◽

Original Idea ◽

Rolling Without Slipping

The orthocycloid represents a plane curve generated by a point belonging to a circle which is rolling without slipping along a line. Our original idea (not approached in the specialty literature) is to consider the rolling with slipping of a wheel on a rail, instead of the rolling of the gear “gearwheel –rack” as in the case of the orthocycloid generation. In this case the length of the arc considered on the circle is no longer equal to the segment from the line supporting the rolling. The tracer point belonging to the wheel will generate other curves but orthocycloids. Various curves were obtained. Analyses were made considering the braking due to the friction between the rolling surfaces and respectively the case when the lubricant layer generates a “skating like” rolling. The yielded curves start from the classical form of the orthocycloid and afterward are distorted exhibiting an increased number of loops. Some curves are similar to elongated orthocycloids, obtained in different conditions. The curves resulted from rolling by slipping can be used in various domains.

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The moulds from Velebit and European bronze age metal anvils

Starinar ◽

10.2298/sta1969139a ◽

2019 ◽

pp. 139-182

Author(s):

Barbara Armbruster ◽

Albrecht Jockenhövel ◽

Aleksandar Kapuran ◽

Rasko Ramadanski

Keyword(s):

Functional Analysis ◽

Social Context ◽

Bronze Age ◽

General Role ◽

Starting Point ◽

History Of ◽

The Village ◽

The Bronze Age ◽

Significant Class

During the first excavations of the cemetery dating from the Bronze Age and Early Antiquity in the village of Velebit near Kanjiza (Northern Serbia) one of the excavated artefacts was found to belong to a used and broken stone mould for casting anvils. However, without an expert archaeologist to supervise the recovery of this find, which remained unknown for decades after its discovery, as a starting point, the authors of this article present a synthesis that takes into account several aspects of this significant class of metalcraft object. This proceeds from the history of the excavation to the general role of European Bronze Age anvils in gold and bronze metalworking, and then further on to their typological, terminological, chronological and functional analysis and to their long-range distribution as a sign of an interregional network of craftsmen, including their social context and symbolism.

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Stereo Electron Microscopy Applied to High Resolution Freeze-Etch Replicas

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100068527 ◽

1970 ◽

Vol 28 ◽

pp. 306-307

Author(s):

L. Andrew Staehelin

Keyword(s):

Electron Microscopy ◽

Plastic Deformation ◽

High Resolution ◽

Smooth Surfaces ◽

Small Particles ◽

Membrane Surfaces ◽

Wide Acceptance ◽

New Information ◽

Number Of Particles ◽

Small Holes

Freeze-etched membranes usually appear as relatively smooth surfaces covered with numerous small particles and a few small holes (Fig. 1). In 1966 Branton (1“) suggested that these surfaces represent split inner mem¬brane faces and not true external membrane surfaces. His theory has now gained wide acceptance partly due to new information obtained from double replicas of freeze-cleaved specimens (2,3) and from freeze-etch experi¬ments with surface labeled membranes (4). While theses studies have fur¬ther substantiated the basic idea of membrane splitting and have shown clearly which membrane faces are complementary to each other, they have left the question open, why the replicated membrane faces usually exhibit con¬siderably fewer holes than particles. According to Branton's theory the number of holes should on the average equal the number of particles. The absence of these holes can be explained in either of two ways: a) it is possible that no holes are formed during the cleaving process e.g. due to plastic deformation (5); b) holes may arise during the cleaving process but remain undetected because of inadequate replication and microscope techniques.

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Crystal structure images of large gold clusters and growing crystals by HRTEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010011218x ◽

1984 ◽

Vol 42 ◽

pp. 428-429

Author(s):

L.R. Wallenberg ◽

J.-O. Bovin ◽

G. Schmid

Keyword(s):

Crystal Structure ◽

Nucleation And Growth ◽

Close Packing ◽

Gold Clusters ◽

Molecular Weight Determination ◽

Growth Mechanisms ◽

Starting Point ◽

Different Types ◽

Nucleation And Growth Mechanisms ◽

Points Of View

Metallic clusters are interesting from various points of view, e.g. as a mean of spreading expensive catalysts on a support, or following heterogeneous and homogeneous catalytic events. It is also possible to study nucleation and growth mechanisms for crystals with the cluster as known starting point.Gold-clusters containing 55 atoms were manufactured by reducing (C6H5)3PAuCl with B2H6 in benzene. The chemical composition was found to be Au9.2[P(C6H5)3]2Cl. Molecular-weight determination by means of an ultracentrifuge gave the formula Au55[P(C6H5)3]Cl6 A model was proposed from Mössbauer spectra by Schmid et al. with cubic close-packing of the 55 gold atoms in a cubeoctahedron as shown in Fig 1. The cluster is almost completely isolated from the surroundings by the twelve triphenylphosphane groups situated in each corner, and the chlorine atoms on the centre of the 3x3 square surfaces. This gives four groups of gold atoms, depending on the different types of surrounding.

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Two isoprenylated flavonoids from Dorstenia psilurus activate AMPK, stimulate glucose uptake, inhibit glucose production and lower glycemia

Biochemical Journal ◽

10.1042/bcj20190326 ◽

2019 ◽

Vol 476 (24) ◽

pp. 3687-3704 ◽

Cited By ~ 2

Author(s):

Aphrodite T. Choumessi ◽

Manuel Johanns ◽

Claire Beaufay ◽

Marie-France Herent ◽

Vincent Stroobant ◽

...

Keyword(s):

Glucose Uptake ◽

Human Cancer ◽

Glucose Production ◽

Liver Mitochondria ◽

New Drugs ◽

Structural Isomer ◽

Rat Liver Mitochondria ◽

Ionization Mass ◽

Ampk Activation ◽

Starting Point

Root extracts of a Cameroon medicinal plant, Dorstenia psilurus, were purified by screening for AMP-activated protein kinase (AMPK) activation in incubated mouse embryo fibroblasts (MEFs). Two isoprenylated flavones that activated AMPK were isolated. Compound 1 was identified as artelasticin by high-resolution electrospray ionization mass spectrometry and 2D-NMR while its structural isomer, compound 2, was isolated for the first time and differed only by the position of one double bond on one isoprenyl substituent. Treatment of MEFs with purified compound 1 or compound 2 led to rapid and robust AMPK activation at low micromolar concentrations and increased the intracellular AMP:ATP ratio. In oxygen consumption experiments on isolated rat liver mitochondria, compound 1 and compound 2 inhibited complex II of the electron transport chain and in freeze–thawed mitochondria succinate dehydrogenase was inhibited. In incubated rat skeletal muscles, both compounds activated AMPK and stimulated glucose uptake. Moreover, these effects were lost in muscles pre-incubated with AMPK inhibitor SBI-0206965, suggesting AMPK dependency. Incubation of mouse hepatocytes with compound 1 or compound 2 led to AMPK activation, but glucose production was decreased in hepatocytes from both wild-type and AMPKβ1−/− mice, suggesting that this effect was not AMPK-dependent. However, when administered intraperitoneally to high-fat diet-induced insulin-resistant mice, compound 1 and compound 2 had blood glucose-lowering effects. In addition, compound 1 and compound 2 reduced the viability of several human cancer cells in culture. The flavonoids we have identified could be a starting point for the development of new drugs to treat type 2 diabetes.

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Overview of Current Approaches to Aural Rehabilitation for Adults With Cochlear Implants

Perspectives of the ASHA Special Interest Groups ◽

10.1044/2020_persp-20-00078 ◽

2020 ◽

Vol 5 (5) ◽

pp. 1175-1187

Author(s):

Rachel Glade ◽

Erin Taylor ◽

Deborah S. Culbertson ◽

Christin Ray

Keyword(s):

Health Care ◽

Clinical Practice ◽

Cochlear Implants ◽

Practice Patterns ◽

The United States ◽

Care Providers ◽

Aural Rehabilitation ◽

Starting Point ◽

Clinical Models ◽

Hearing Health

Purpose This clinical focus article provides an overview of clinical models currently being used for the provision of comprehensive aural rehabilitation (AR) for adults with cochlear implants (CIs) in the Unites States. Method Clinical AR models utilized by hearing health care providers from nine clinics across the United States were discussed with regard to interprofessional AR practice patterns in the adult CI population. The clinical models were presented in the context of existing knowledge and gaps in the literature. Future directions were proposed for optimizing the provision of AR for the adult CI patient population. Findings/Conclusions There is a general agreement that AR is an integral part of hearing health care for adults with CIs. While the provision of AR is feasible in different clinical practice settings, service delivery models are variable across hearing health care professionals and settings. AR may include interprofessional collaboration among surgeons, audiologists, and speech-language pathologists with varying roles based on the characteristics of a particular setting. Despite various existing barriers, the clinical practice patterns identified here provide a starting point toward a more standard approach to comprehensive AR for adults with CIs.

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Indirect Assessment of Attitudes with Response-Time-Based Measures

Zeitschrift für Sozialpsychologie ◽

10.1024/0044-3514.37.3.131 ◽

2006 ◽

Vol 37 (3) ◽

pp. 131-139 ◽

Cited By ~ 15

Author(s):

Juliane Degner ◽

Dirk Wentura ◽

Klaus Rothermund

Keyword(s):

Social Cognitive ◽

Incremental Validity ◽

Self Report ◽

Small Scale ◽

Implicit Measures ◽

Scale Theory ◽

Starting Point ◽

Self Reports ◽

Predicting Behavior ◽

Social Cognitive Theories

Abstract: We review research on response-latency based (“implicit”) measures of attitudes by examining what hopes and intentions researchers have associated with their usage. We identified the hopes of (1) gaining better measures of interindividual differences in attitudes as compared to self-report measures (quality hope); (2) better predicting behavior, or predicting other behaviors, as compared to self-reports (incremental validity hope); (3) linking social-cognitive theories more adequately to empirical research (theory-link hope). We argue that the third hope should be the starting point for using these measures. Any attempt to improve these measures should include the search for a small-scale theory that adequately explains the basic effects found with such a measure. To date, small-scale theories for different measures are not equally well developed.

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The Solidarity of Distance1

Zeitschrift für Sozialpsychologie ◽

10.1024/0044-3514.36.3.103 ◽

2005 ◽

Vol 36 (3) ◽

pp. 103-115 ◽

Cited By ~ 3

Author(s):

Robert A. Wicklund

Keyword(s):

Physical Contact ◽

Emotional Distance ◽

Starting Point ◽

Shared Emotions ◽

Common Goals ◽

Full Interaction ◽

The Individual ◽

Social Incompetence

Abstract: Solidarity in the classic sense pertains to a cohesion among humans that entails physical contact, shared emotions, and common goals or projects. Characteristic cases are to be found among families, close friends, or co-workers. The present paper, in contrast, treats a phenomenon of the solidarity of distance, a solidarity based in fear of certain others and in incompetence to interact with them. The starting point for this analysis is the person who is motivated to interact with others who are unfamiliar or fear-provoking. Given that the fear and momentary social incompetence do not allow a full interaction to ensue, the individual will move toward solidarity with those others on a symbolic level. In this manner the motivation to approach the others is acted upon while physical and emotional distance is retained.

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